Fechner, Gustav Theodor (1801–1887)

Gustav Fechner was a German physicist and founder of experimental psychologist, usually remembered
for his reformulation of Ernst Heinrich Weber's (1795–1878) conclusions
concerning the increase in a stimulus needed to make someone aware that
there was a difference. Fechner's law (or the Weber-Fechner
law) states that the perceived intensity of a sensation increases with the
logarithm of its stimulus.

Among his other work, Fechner studied aesthetic aspects of the golden
ratio and published his findings in Vorschule der Aesthetik (1876), arguing that this ratio turns up commonly in human-made rectangular
objects and is judged by people to be the most pleasing to the eye (though
some later researchers have called his results into question).